1. Technical Field
This invention relates generally to networks for wireless communication with portable electronic devices, and more specifically to a method and apparatus for mobile nodes, such as mobile telephones and portable computers, to determine whether a foreign network is capable of multiple Internet Protocol (IP) address communication.
2. Background Art
Mobile device communication with networks is becoming more advanced as the mobile devices are equipped with new applications and features. Not too long ago, a mobile telephone was only used for voice communication. Analog signals were capable of accommodating high-quality voice communication across networks. As these mobile devices became more advanced, the analog networks gave way to digital networks. Mobile telephones became mobile communication devices capable not only of transmitting voice calls, but also text messages, multimedia messages, pictures, video, music, and so forth. Further, other devices, including personal digital assistants and portable computers, began to use the “cellular” networks originally designed for mobile telephones. Designers quickly realized that communication standards were required to facilitate transfer of mobile devices between cells and to facilitate the variety of communication modes associated with each device.
Mobile Internet Protocol communication (Mobile IP) became an accepted standard for such communication. Mobile IP is a network-based communication protocol that facilitates digital, packet based “datagram” communication between mobile devices, referred to herein as “mobile nodes,” to travel from one network to another while maintaining advanced communication capability. One recognized standard associated with a current network technology is referred to as IPv4, and is set forth in several standards, including “RFC 3344—IP Mobility Support for IPv4,” published by the Network Working Group of the Internet Society in August, 2002, with C. Perkins Editor, which is incorporated herein by reference.
IP mobility support for IPv4 “ . . . specifies protocol enhancements that allow transparent routing of IP datagrams to mobile nodes in the Internet. Each mobile node is always identified by its home (IP) address, regardless of its current point of attachment to the Internet. While situated away from its home, a mobile node is also associated with a care-of (IP) address, which provides information about its current point of attachment to the Internet. The protocol provides for registering the care-of address with a home agent. The home agent sends datagrams destined for the mobile node through a tunnel to the care-of address. After arriving at the end of the tunnel, each datagram is then delivered to the mobile node.”
IP mobility support for IPv4 permits mobile nodes, such as mobile telephones and personal digital assistants, to travel between various networks across geographic regions while maintaining their datagram communication capability with each network. Without standards such as this, a mobile node would “drop” communication channels as it transitioned from one network to another. This is true because the IP addresses associated with IP-based communication are generally location specific. When a person takes a mobile node from one network to another, that mobile node is incapable of employing the home IP address for communication with not in its home network.
While networks and devices employing the IP mobility support for IPv4 work well in practice, they do have limitations. One such limitation is that the Internet Multimedia Standard (IMS) for IPv4, in some applications, presumes that datagram content for applications and communication will be Session Initiation Protocol (SIP) based communication. As such, these networks are configured to efficiently handle SIP-based content, but generally are either inefficient or incapable of handling non-SIP based content. Further, traditional IMS networks are sometimes not well suited to regulate policy controls over SIP and non-SIP applications, nor are they effective at prioritizing or allocating network resources such as quality of service, security, packet flow optimization, or service provider access control in accordance with subscriber service contracts.
To alleviate some of these problems, designers have been working on a new IMS, known by some as A-IMS or “Advances to IMS.” Specifically designers of hardware and networks have proposed standards that employ a dual or multiple-IP address communication scheme. By way of example, in one embodiment, a mobile node communicates through a “dual anchoring” scheme. In dual-anchoring, agents of networks establish two IP addresses with each mobile node. A first may be anchored in a bearer manager associated with a foreign network, while another is anchored in a bearer manager associated with a home network. Contracts with users and policies associated with service providers determine which IP address is used for which application. By way of example, a time sensitive application such as a game or video application may use the IP address associated with the foreign network, while other less-time sensitive applications may use the IP address associated with the home network.
Such a new network protocol presents problems for mobile node manufacturers. Single-IP address devices are not configured to communicate with multiple-IP address interface based systems. Similarly, a mobile node attempting to employ multiple IP address communication with a legacy network will not be successful in establishing multiple IP addresses. Consumers desire devices that work across a variety of networks, including single IP address and multiple IP address based networks.
There is thus a need for a method and apparatus capable of differentiating between single IP address based networks and multiple IP address based networks.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.